Benedict, recommend having your indy (or another reputable one) carefully inspect the pistons and connecting rods on the damaged bank to determine if replacement is necessary ... probably not. Have both heads reworked at a machine shop with valve stem seals replaced, as a minimum, on the good head ... whatever it takes to make both like new. Go ahead and replace the timing chain, tensioner and all guide rails ... no sense measuring the timing chain stretch at this point.

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Fred Hoelzle